The present invention relates to a hydraulic machine, in particular, a flange member provided around a fluid inlet opening or a fluid outlet opening of a hydraulic machine for connection of the opening with an outside conduit means.
In a hydraulic machine such as a pump, it is common for a flange to be provided around a fluid inlet opening and/or a fluid outlet opening so that, when a separate outside conduit means is connected to the opening, a flange provided at an end of the conduit means is aligned with and connected to the flange of the fluid machine and securely fastened by fastener means such as bolts and nuts.
FIG. 5 shows an example of such a conventional flange provided on a hydraulic machine. In this example, a short tubular member 12 is connected at a rim of an opening of the machine at one end thereof and is provided at the other end with a flange member 18 made of a sheet like member. The flange member 18 is provided on its inside surface with an annular reinforcement member 22, and the reinforcement member is supported by a bracket 24. When a conduit member is connected to the flange member 22, a flange of the conduit member is engaged with the flange 18 with a gasket being interposed therebetween and fastened to the flange 18 by means of bolts and nuts or the like.
In this conventional art, the members 22 and 24 for reinforcing the flange 18 are prepared separately from the flange in order to reduce an amount of nonferrous metal material to be used to form elements that come into contact with a fluid passing through the machine in operation thereby reducing costs.
FIG. 6 shows another conventional art in which a flange 30 is integrally formed with a body of a hydraulic machine and machined to form an O-ring receiving groove in its surface. When connected to a conduit means, the flange is provided with an O-ring in the groove to hermetically seal the connection between the flange and the conduit means.
However, the above-noted conventional arts involve the following problems.
In the first conventional art, in order to assure sealing of the connection between the flange member 18 and a conduit means connected thereto, it is necessary for the flange member 18 to have a highly finished surface. However, heat transmitted to the flange member 18 during welding of the reinforcement member 22 to the flange member 18 affects the surface of the flange member 18 and causes a deterioration in the degree of finishing of the surface. Further, since the flange member 18 is generally formed of stainless steel, a friction coefficient of the surface of the flange member 18 is small and thus a gasket interposed between the flange member 18 and a conduit connected thereto tends to slide thereby causing a lowering in sealing therebetween.
The conventional art shown in FIG. 6 involves a problem of high costs in producing the flange 30 as machining of the flange is required to form the O-ring receiving groove 32.
In light of the above-noted problems in the conventional arts, the present invention is directed to a flange member which can facilitate formation of a highly reliable seal and can be produced at low cost, a hydraulic machine with such a flange and a method of production thereof.
The present invention provides an annular flange member adapted to be provided around a fluid passage opening of a housing of a hydraulic machine to connect a fluid conduit means to the fluid passage opening. The annular flange member comprises an inside surface facing the housing, an outside surface opposite the inside surface, and a through hole extending from the inside surface to the outside surface and fluidly communicated with the fluid passage opening. The outside surface is provided with a press formed O-ring receiving groove surrounding the through hole.
The O-ring receiving groove may be formed by a half die cutting press operation.
Specifically, the flange member may include an annular projection formed on the inside surface corresponding to the O-ring receiving groove and a recess formed in the inside surface around a root of the annular projection.
Further, the present invention provides a hydraulic machine including a housing having a fluid passage opening, wherein the hydraulic machine comprises a flange member formed separately from the housing and provided at the fluid passage opening, and the flange member is an annular member having an inside surface facing the housing, an outside surface opposite the inside surface and a through hole extending from the inside surface to the outside surface and fluidly communicated with the fluid passage opening, the outside surface being formed with a press formed O-ring receiving groove therein surrounding the through hole.
Furthermore, the present invention provides a method of producing a flange member provided around a fluid passage opening in a housing of a hydraulic machine. The method comprises the steps of preparing a plate-like member having opposing surfaces including first and second surfaces, forming a through hole in the plate-like member which extends between the first and second surfaces and is adapted to be fluidly communicated with the fluid passage opening, and subjecting the plate-like member to a press operation to form an O-ring receiving groove in the first surface in such a manner that the O-ring receiving groove surrounds the through hole.
The present invention also provides a method of producing a hydraulic machine. The method comprises the steps of producing a housing of the machine provided with a fluid passage opening, and producing a flange separately from the housing adapted to provided around the fluid passage opening. The step of producing the flange comprises preparing a plate-like member having opposing surfaces including first and second surfaces, forming a through hole in the plate-like member which extends between the first and second surfaces and is adapted to be fluidly communicated with the fluid passage opening, and subjecting the plate-like member to a press operation to form an O-ring receiving groove in the first surface in such a manner that the O-ring receiving groove surrounds the through hole.
According to the present invention, a fluid passage opening flange of a hydraulic machine is prepared separately from a housing of the hydraulic machine, whereby it becomes easy to produce the flange. Further, since an O-ring receiving groove is formed in an outside surface thereof on which an opening flange of an outside conduit means is engaged, it is possible to achieve reliable sealing of a connection between the flange and a conduit means connected thereto by placing an O-ring in the O-ring receiving groove.